From b99ef2541f098d522e30ca7df58b27987a4b3998 Mon Sep 17 00:00:00 2001
From: Larry <92799281+brilliant-lx@users.noreply.github.com>
Date: Wed, 15 Mar 2023 17:43:18 +0800
Subject: [PATCH] fix: crash on nil access when TxPool shutdown (#1353)

---
 miner/worker.go | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/miner/worker.go b/miner/worker.go
index 599032c217..d44187f928 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -1126,7 +1126,12 @@ LOOP:
 		// subscribe before fillTransactions
 		txsCh := make(chan core.NewTxsEvent, txChanSize)
 		sub := w.eth.TxPool().SubscribeNewTxsEvent(txsCh)
-		defer sub.Unsubscribe()
+		// if TxPool has been stopped, `sub` would be nil, it could happen on shutdown.
+		if sub == nil {
+			log.Info("commitWork SubscribeNewTxsEvent return nil")
+		} else {
+			defer sub.Unsubscribe()
+		}
 
 		// Fill pending transactions from the txpool
 		fillStart := time.Now()
@@ -1196,7 +1201,9 @@ LOOP:
 		}
 		// if sub's channel if full, it will block other NewTxsEvent subscribers,
 		// so unsubscribe ASAP and Unsubscribe() is re-enterable, safe to call several time.
-		sub.Unsubscribe()
+		if sub != nil {
+			sub.Unsubscribe()
+		}
 	}
 	// get the most profitable work
 	bestWork := workList[0]